Which of the following is true regarding the cultivation and isolation of animal viruses?

• A. Animal viruses can be cultivated using nutrient agar plates alone.
• B. Animal viruses cannot be grown in cell cultures.
• C. Bacterial hosts are required for the isolation of all animal viruses.
• D. Embryonated eggs are commonly used for the cultivation of animal viruses.

Answer: (D)

Verified step by step guidance

1. Understand that animal viruses require living cells to replicate because they are obligate intracellular parasites and cannot grow on nutrient agar plates like bacteria.
2. Recognize that animal viruses can be cultivated in cell cultures, which provide the necessary living host cells for viral replication.
3. Know that bacterial hosts are not used for the isolation of animal viruses, as bacteria are hosts for bacteriophages, not animal viruses.
4. Learn that embryonated eggs are a traditional and common method for cultivating animal viruses because they provide a living environment with multiple cell types suitable for viral growth.
5. Conclude that the statement 'Embryonated eggs are commonly used for the cultivation of animal viruses' is true, while the other options are false based on the biology of animal virus cultivation.